Satellite Roller Screw Actuation for Precise Load-Speed Modulation
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Solution Overview
Problem
Current roller screw mechanisms are limited by high cost, bulkiness, and inability to achieve high linear motion accuracy at low speeds under heavy loads or high linear travel speeds at low loads, while also requiring separate mechanisms for linear and rotational movements.
Innovation Solution
A compact actuation mechanism combining a roller screw mechanism with a main and secondary rotary drive means, featuring a satellite roller screw design with an annular guide for roller holding, allowing for optimized linear displacement precision and speed, and enabling combined linear displacement and rotational movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a satellite roller screw mechanism is used to achieve high load capacity, then the allowable load increases, but the linear motion accuracy at low speeds deteriorates
Solution Approach 1:
The patent merges two separate screw mechanisms (one for linear motion, one for rotational motion) into a single integrated satellite roller screw mechanism. The nut is made movable in both translation and rotation relative to the rollers, allowing simultaneous achievement of linear displacement and rotational displacement with a single compact mechanism, thereby resolving the contradiction between load capacity and precision by optimizing the unified mechanism's parameters.
Solution Approach 2:
The patent changes the operational parameters of the satellite roller screw mechanism by allowing the nut to move in both translation and rotation. This parameter change enables the mechanism to achieve high linear motion accuracy at low speeds under heavy loads by optimizing the relationship between rotational speed, linear displacement, and rotational displacement parameters.
2Adaptability or versatility
If separate screw mechanisms are used for linear and rotational movements, then both movements can be achieved, but the device complexity and bulk increase
Solution Approach 1:
The patent combines two separate screw mechanisms into one integrated satellite roller screw mechanism. The nut is made movable in both translation and rotation relative to the rollers, allowing simultaneous achievement of linear displacement and rotational displacement with a single compact mechanism, thereby reducing device complexity and bulk while maintaining versatility.
Solution Approach 2:
The satellite roller screw mechanism is designed to perform multiple functions simultaneously: it provides both linear motion and rotational motion through a single mechanism. The nut's ability to move in translation and rotation makes the mechanism universal, capable of achieving combined linear and rotational displacements without requiring separate dedicated mechanisms.
3Manufacturing precision
If the thread pitch is optimized for high linear motion accuracy at low speeds, then precision improves, but the linear travel speed at low loads deteriorates
Solution Approach 1:
The patent introduces dynamic capability to the mechanism by allowing the nut to move in both translation and rotation. This dynamic configuration enables the system to adapt between different operational modes: optimizing for high precision at low speeds when needed, and achieving high linear travel speeds at low loads when needed, by adjusting the relationship between rotational and translational movements.
Solution Approach 2:
The patent changes the operational parameters by enabling coupled rotational and translational motion. This parameter change allows the mechanism to achieve high linear motion accuracy at low speeds under heavy loads, while also enabling high linear travel speeds at low loads, resolving the contradiction through optimized parameter relationships in the unified mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high precision and speed in linear and rotational displacement, reducing costs and bulkiness, while allowing for modulation of displacement speed and improved accuracy by controlling combined rotational speeds.
Implementation Method 1
a screw comprising an external thread, a nut arranged around the screw and comprising an internal thread, and a plurality of longitudinal rollers in engagement with the external and internal threads of screw and nut, respectively
Implementation Method 2
a plurality of longitudinal rollers in engagement with the external and internal threads of screw and nut, respectively
Data Source
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AI summary
The invention relates to an actuation mechanism (30, 40, 60, 70) comprising a main rotational drive means (31, 41, 61, 71) and a roller screw mechanism (1, 43, 73) coupled to said drive means (31, 41, 61, 71). The roller screw mechanism (1, 43, 73) comprises a screw (2, 82), a nut (4, 84), and a plurality of rollers (6, 86), one of the screw (82) and the nut (4) being coupled to the main rotational drive means (31, 41, 61, 71), the other (2, 84) being movable in translation and rotation relative to the rollers (6, 86). The roller screw mechanism (1, 43, 73) also includes an annular guide (14, 44, 88) for circumferential and axial retention of the rollers (6, 86).The annular guide (14, 44, 88) includes a cylindrical sleeve (21, 45, 46, 90) extending axially from one of the annular heels (15, 16) outwards beyond the nut (4, 84), the screw (2, 82) extending in a bore of said sleeve (21, 45, 46, 90), said sleeve (21, 45, 46, 90) being coupled to a secondary rotation drive means (32, 42, 62, 72).